Cardiovascular Drugs include medications that affect the heart and blood vessels as well as the anticoagulants. Here are the list I got.
1. Cardiac Glycosides occurred widely in nature or can be prepared naturally. Also called cardiotonic as it strengthens the heart beat. Increase the force of myocardial contractions and thus slow the heart rate. Used primarily in the treatment of congestive heart failure. It increases the force of cardiac contraction which increases the cardiac output without increasing the oxygen consumption. The heart beats slower as a result.
The most commonly used cardiac glycosides are digitalis products. Of these digoxin (Lanoxin) is used most frequently because it can be administered orally and parentally and has intermediate duration of action.
Digitalization is the process of establishing correct therapeutic dose of digitalis for maintaining optimal functioning of the heart without toxic effects. This is very important because digitalis has a very narrow margin between effective therapy and dangerous toxicity. Check apical pulse before administering digitalis. If heart rate is lower than 60 beats per minute, withhold the med for physician consultancy. It is also important to adjust the dosage for digoxin when changing from tablets or IM therapy to liquid-filled capsules or IV therapy.
Toxic side effects of digoxin include cardiac arrhythmias of all kinds (especially bradycardia of rate less than 60), electrolyte imbalance, abdominal cramping, distention and confusion. It is contraindicated for people with hypothyroidism.
Treatment of digitalis toxicity include atropine for sever bradycardia. Even though atropine is a anticholinergic, here it works paradoxically with vagus nerve to bring heart rate down. In life-threatening digoxin toxicity, Digoxin immune Fab is used as an antidote. Also note that barbiturates such as phenobarbital or phenytoin reduce digitalis levels.
2. Antiarrhythmic Agents include variety of drugs that act in different ways to suppress various types of cardiac arrhythmias, including atrial ventricular tachycardias, atrial fibrillation or flutter or arrhythmias that occur with digitalis toxicity or during surgery and anesthesia. Take all antiarrhythmic meds with full glass of water on empty stomach, one hour before or two hour after meals.
- Adrenergic Blockers. Beta adrenergic blockers produce a membrane stabilizing effect on the heart. It can cause bradycardia, hypotension, CNS symptoms, bronchospasm and hypoglycemia.
- Calcium Channel blockers such as Verpamil (Isoptin) counteracts arrhythmias by suppressing the action of calcium channel in contraction of heart muscle, thereby reducing the cardiac excitability and dilating the main coronary arteries. They are used in angina and hypertension treatment. It has antagonistic effect with barbiturates, salicylates and lithium.
- Lidocaine is local anesthetics with antiarrhythmic and membrane-stabilizing action. It’s a second-line antiarrhythmic agent behind IV amiodarone for the treatment of ventricular arrhythmias. Lidocaine has short-term effect and is usually dose-related.
Now remember that although usually antiarrhythmic agents reduce heart rate, sometimes they can cause tachycardia as well. Anticholinergic-antiarrhythmic agents such as procrainamide, quinidine and disopyramide do that and they maintain heart rhythm prophylactically. Quinidine and disopyramide also depresses the strength of myocardial contraction.
- Procrainamide is administered orally and primarily as prophylactic therapy to maintain normal rhythm after conversion by other methods. It posses anticholinergic properties, so it causes tachycardia and assystole. Procrainamide is contraindicated in heart block and CHF, myasthenia gravis and Systemic Lupus Erythematous (LSE).
- Qunidine, like procrainamide and disopyramide, is used primarily as prophylactic therapy to maintain normal rhythm after conversion by other methods. What quinidine does differently along with disopyramide is that it depresses myocardial contractibility.
- Disopyramide or Norpace like quinidine depress myocardial contractility and shouldn’t be used with heartblock and CHF.